The present invention relates to mowers of the cross-flow blower type and provides an automatic brake/sharpener for such mowers.
Mowers of the cross-flow blower type are described in my U.S. Pat. No. 3,673,773 and comprise a cylindrical reel having a plurality of spaced blades horizontally mounted on a carriage with the reel axis extending laterally of the carriage. A blower conduit cooperates with the reel to form a blower of the cross-flow or transverse-flow type. The outer leading edges of the blades are sharp to form cutting edges. No bed knife or shear plate is employed. In the preferred arrangements the reel rotates in a direction such that the lower blades move in the forward direction with respect to the normal direction of travel of the mower, and the outer edges of the blades are forwardly hooked.
In mower operation air is drawn into the blower from in front of the mower and draws the grass toward the forwardly moving lower blades so that the grass is cut effectively. The grass clippings are discharged from the outlet of the blower and may be directed toward the ground, discharged to the side, or collected in a grass catcher.
In a cross-flow blower air is drawn into the rotor at the inlet region, passes through the interior of the rotor, and then passes out of the rotor at the outlet region. Thus the air passes through the blades twice in a direction transverse to the rotor axis. Vortex components around the blades are involved in the functioning of the blower.
In my U.S. Pat. No. 3,818,684 certain improvements are described including a forward extension on the housing which causes an auxiliary vortex to be developed.
In my application Ser. No. 741,132, supra, improvements are described for reducing blower noise while preserving good mowing performance, and even enabling enhanced performance. In the specific embodiments of FIGS. 1-3 other features are described in order to illustrate a preferred mower construction. Novel blade structures are described and the term "rotor" is employed. The term "rotor" is used herein to include such structures as well as the structures of U.S. Pat. No. 3,673,773, etc.
In order to cut grass cleanly, with minimum fraying, the cutting edges of the blades should be reasonably sharp. This is also true of conventional types of mowers such as rotary mowers and reel mowers with bed knives or shear plates. Some dulling of the blades may be acceptable, and is commonly tolerated in practice due to the trouble and/or expense involved in keeping the blades sharp. Nevertheless, sharp blades are desirable for best performance.
Various types of sharpeners have been suggested, particularly for conventional reel mowers. Some are attachments which must be manually mounted on the mowers. Others are mounted on the mower and manually moved into sharpening position. Both types require manipulation by the user, and some degree of care and attention, and widespread use has not been attained. In the case of rotary mowers, it is common to remove the blades from the machine for sharpening, or to employ special grinding wheels in a power tool.
In my U.S. Pat. No. 3,659,385, a sharpening attachment is described for mowers of the cross-flow type. Since this also requires manipulation, a user may not go to the trouble of keeping the blades sharp, even if the attachment is provided.